In the next seven days, the Obama-who-got-Osama is due to give two major foreign policy speeches. The first, to be delivered tomorrow in Washington, is about the Middle East. Following his seminal 2009 Cairo speech to the Muslim world, this is billed as "Cairo 2". It is intended to lay out a vision and a strategy for American policy towards the whole region, and to do that before Israeli prime minister Binyamin Netanyahu arrives in Washington. It is also meant to refute the claim, attributed to one of Obama's advisers in a recent New Yorker article, that in foreign policy he has been "leading from behind". That's not how a president wants to be seen going into a re-election year.

I'm told that the second speech, to be delivered in London next Wednesday, will be about Europe and transatlantic relations. This will come in the middle of a European tour that includes a visit to his great-great-great-great-great grandfather's birthplace of Moneygall in Ireland; all the pomp and circumstance of a state visit to Britain as the guest of Her Majesty the Queen; the G8 meeting at Deauville in France; and two days in Poland, where White House genealogists must surely be able to find some great-great-great-great-great aunt in the little town of, say, Ustrzyki Dolne, to help boost his Polish-American as well as his Irish-American vote in 2012.

Obama will deliver his European keynote in the medieval Westminster Hall, a venue in which, since 1945, only three other foreign dignitaries have had the honour of addressing both Houses of Parliament: Charles de Gaulle, Nelson Mandela and Pope Benedict XVI. That makes two towering predecessors. So a great venue has been agreed but I will bet you the content of the speech has not. As I write, they're still sweating over the first one.

From what I can gather, the two speeches are not yet conceived as a strategic pair. They should be. There is no project on which strategic partnership between Europe and the United States is more urgently needed than that of responding to the most important single political development of the early 21st century: the Arab spring.

I do not say this for the sake of finding something that the two halves of the now-vanished cold war "west" can do together; I say it because it is simply a fact that neither side of the Atlantic can do this on its own. Only the US can (just possibly, even with so many Israeli settlers the wrong side of the line) persuade Israel to embrace a two-state solution; only the Europeans can provide the aid, know-how, trade and investment to enable the building of a viable Palestinian state. Only the US has sufficient clout with the Egyptian military to prevent them strangling their country's new democracy at birth. That fledgling democracy cannot, however, grow without access to European markets, education and support across the Mediterranean. And so it goes on, in every case from Morocco to Pakistan – if we include Pakistan in a generous definition of the wider Middle East.

So Euro-Atlantic partnership is not an end in itself, it is the necessary means to a shared end. Our shared purpose must be to help the Arab spring become a lasting freedom summer for the whole of the Islamic world. This should be the third great project of transatlantic partnership since the second world war.

First, there was the reconstruction of western Europe after 1945, symbolised by the Marshall Plan, the founding of Nato, the Council of Europe and the institutions that would eventually develop into today's EU. Here, the US was by far the strongest partner.

Second, there was the integration of central and eastern Europe into what central Europeans such as Vaclav Havel christened the "Euro-Atlantic structures". Here, the US and Europe were equal partners. The key symbolic moments were the eastward enlargement of Nato in 1999 and of the EU in 2004.

In this third project, the potential power of the EU to effect peaceful change is somewhat greater than that of the remote and relatively weakened US. North Africa and the Middle East are, after all, Europe's near-abroad. In responding to movements of self-liberation, the economic, social, legal, administrative and cultural dimensions of power – in which Europe is rich – are more relevant than the hard military ones, in which the United States remains supreme. Europe's potential power, I stress: for Europe is doing a terrible job of translating potential into actual power.

But this is the speech of the one-and-only American president, not that of one of Europe's seeming innumerable soi-disant presidents (of the European commission, parliament, council, etc).

Obama's foreign policy has so far been characterised by what is politely called "realism". During the presidential campaign he himself said "the truth is that my foreign policy is actually a return to the traditional bipartisan realistic policy of George W Bush's father, of John F Kennedy, of, in some ways, Ronald Reagan". So far, his priorities have been: security first, development second, democracy and human rights a very poor third. The passions of his youth – civil resistance in the tradition of Martin Luther King, social self-organisation, liberation – have hardly been visible in the actions of the president.

This is the perfect moment for him to open a new foreign policy chapter, infused with a little more of that passion for democracy. The killing of Osama bin Laden has proved that he can be tougher and more effective than George W Bush when it comes to fighting terrorists. No longer need he fear Fox News jibes about being a woolly, third-worldie, former "community organiser" – soft on terrorism, soft on the causes of terrorism. Meanwhile, the wonderful eruption of people power across the Arab world cries out for a response from an heir to Martin Luther King. Between them, these two events have already opened the new chapter.

The tone will not be easy to find. An American president today cannot speak to the Islamic world, or to Europe, as Truman did 65 years ago to the communist world and to western Europe. Neither Europeans nor Arabs are prepared to take their marching orders from Washington. At a Google event today, I asked Wael Ghonim, the Facebook community organiser who was instrumental in starting the Egyptian revolution, what Obama should say in his "Cairo 2" speech tomorrow. Ghonim was reluctant to give advice, but observed that "people in the Middle East" don't like to hear the US telling them which way to go. He added that he wanted to hear "more [about] values rather than just interests". Early indications suggest that the president has heard that message, and will describe the US role as that of a "facilitator" in the Middle East.

As for Europe, it is not ready to be told what to do, even by Obama. But this master wordsmith can surely find a way to talk about America's role in the wider Middle East, while also indicating what he hopes Europe can do – in a strategic partnership of equals.

Step forward in Westminster Hall, Mr President, to help us define the third great transatlantic project of the post-1945 world.